During transportation of cosmetic products, it is not uncommon for them to encounter extreme temperature conditions, such as freezing or overheating. Thus, it is necessary for cosmetic products to be able to withstand a certain degree of temperature changes in transport.
Freeze-thaw cycle testing is a part of stability testing that allows you to determine if your formula will remain stable under various conditions. This type of test puts your sample through a series of extreme, rapid temperature changes that it may encounter during normal shipping and handling processes. Freeze-thaw stability testing is highly recommended, especially for liquid-based cosmetics. These products may experience phase separation that can negatively affect the intended function.
Freeze-thaw testing is conducted by exposing the product to freezing temperatures (approximately -10 °C) for 24 hours, and then allowing it to thaw at room temperature for 24 hours. The sample is then placed in a higher temperature (approximately 45°C) for 24 hours and then placed at room temperature again for 24 hours. The sample is analyzed for significant changes. This completes one cycle. If, after three cycles of freeze-thaw testing, no significant changes are observed, you can be confident that the stability of your product is sufficient for transport.